1. Field of the Invention
The present invention relates to a data transmission method for transmitting and receiving data, such as video and/or audio data in which additional information data (i.e., data hiding or water mark, etc.) are embedded or concealed, and apparatuses for transmitting and reproducing such the video and/or audio data, and in particular, relates to data transmitting and reproducing apparatuses for embedding and detecting the additional information data which are embedded or concealed into the data being transmitted, as well as an information recording medium therefor.
2. Description of Prior Art
Up to now, data hiding has been studied or researched as a technology for embedding or concealing an identification information and/or an annotation into original contents in a form of, such as text data and/or audio/video data. In recent years, the data hiding technology begins to be applied as a technology for protecting a copy right from illegal operations, such as copying of the original data, by embedding such the identification information into them. Such the technology is described in “Data Hiding Technology for Supporting Electronic Water Mark (Upper)”, pages 149 through 162, NIKKEI ELECTRONICS 1997.2.24 (no. 683), by Nikkei Business Publications, Inc.
The data being embedded into the original data, however, are deteriorated through various operations including, such as a filtering, a data compression and so on, thereby, they sometimes happen to be removed from them, for instance, in particular, after encoding/decoding (or converting/inverting) operation thereof. Therefore, such the hidden data are inserted or embedded in the original data or the like repetitively, so as not to be deleted therefrom easily.
However, in the prior art mentioned in the above, there is no description or teaching about a concrete and/or practical way of reproducing the additional information data which are embedded into the original data repetitively, with a low error rate.
Since the video or picture data is large in an amount thereof, therefore, normally it is transferred after being compressed. The transferred data is then de-compressed to be restored into the original data, however, it is impossible to restore them back to the original ones perfectly or completely, due to the processes of such the compression/de-compression. Further, when transmitting the data, errors may occur in the data depending on the route of the data transmission. For restoring such the erred data, it is ordinary to add an error correction code onto it previously, and then so-called correction of the erred data can be performed therewith. However, in the restoration of the data with such the error correction code, though it is possible to detect the error(s) occurring in the data, it is sometimes impossible to restore or correct them if the reliability of the data itself cannot be ensured at a level higher than a certain level. Therefore, it is necessary that an error rate of the data being transmitted must be reduced as low as the error correction is possible to be applied in the level or degree thereof.